Production of synthetic threads



Sept. 22; 1936. 5 |-||ERS 2,055,292

PRODUCTION OF SYNTHETIC THREADS Filed June 6, 1934 WITNESSES: Y

INVENTOR:

Patented Sept. 22, 1936 UNITED STATES PATENT OFFICE Application June 6, 1934, Serial No. 729,251

6 Claims.

This invention relates to methods of and apparatus for producing synthetic threads from viscous solutions such as aqueous dispersions of latex or compositions thereof; artificial dispersions of reclaimed or of crude rubber; dispersions of rubber in organic solvents; cupra-ammonium cellulose; cellulose acetate; nitro-cellulose; etc.

Ordinarily, syntheticthreads are formed from these various emulsions or solutions by expulsion 10 or extrusion through nozzle orifices, and by subsequent treatment of the resulting filaments either with heat or by subjection of them to liquid coagulants, as necessary, to vulcanize or harden them for capacity to withstand tension or strain in their subsequent service as threads. The production of synthetic threads by the old method just briefly outlined, entails the use of complicated and costly apparatus, and requires the maintenance of very exacting operating conditions for predetermination of a product which is uniform in thickness or gauge.

My invention is directed, in the main, toward the provision of an improved method as well as of a simplified apparatus whereby synthetic threads of various cross sectional configurations may be more economically produced in quantity from any of the aforementioned materials, with assurance of absolute regularity as regards uniformity of gauge and quality.

Other objects and attendant advantages will be manifest from the detailed description following in connection with the attached drawing, wherein Fig. I is a longitudinal sectionalview showing more or less diagrammatically, a novel apparatus 5 suitable to the practice of my new method of producing elastic threads from aqueous dispersions of latex or rubber or the like.

Fig. II is a detail plan view on a larger scale showing a circumferentially' grooved cylinder and 40 a cooperating doctor roll, which, taken together, constitute the forming means of the apparatus, the cylinder being partly broken out and sectioned to better .illustrate the character of its grooves.

Figs. III, IV, V and VI are fragmentary detail 5 views on a larger scale, showing cross sectional profiles of different types of grooves for the cylinder; and

Fig. VII is a view corresponding to Fig. I, showing a modified form of apparatus which is especially suited to the production, in accordance with my invention, of synthetic yarns fromcellulose solutions and the like.

With more detailed reference first to Figs. I and II of these illustrations, the numeral 1 comr5 prehensively designates the forming cylinder which has been referred to above. As shown, this forming cylinder I is of hollow construction and adapted to be heated, for example, by continuous circulation of steam or other fluent heating medium through it, and provided, as shown in Fig. II, with a series of laterally spaced circumferential grooves 8 of square cross sectional configuration. In practice, the cylinder 1 is suitably journalied for rotation in fixed bearings (not shown) and constantly driven in the direction of the arrow in Fig. I, its lower portion dipping into a receptacle 9 containing an aqueous dispersion S of latex 'or rubber from which the synthetic threads are to be produced. Running in circumferential pressure contact with the forming cylinder l and rotating in the same direction, is a doctor roll Ill; and overlying a portion of the circumference of the cylinder at the top is a coagulating chamber 1 i which is internally heated. Incident to rotation of the forming cylinder I in the receptacle 9, its grooves are filled with the solution S, any excess of the latter carried on the surface of said cylinder, being removed by action of the doctor roll l0 and dropping back into the receptacle. If found desirable or convenient in practice a scraper or doctor blade may be used in lieu of the doctor roll in herein illustrated. After passing through the coagulating chamber H, the strands of the material filling within the grooves of the forming cylinder 1 are set or hardened to a certain extent and thus rendered sumciently strong for removal as filaments F by a draw-off roller l2, the setting or hardening being materially promoted by the internal heating of said cylinder. The filaments F are finally passed through a drying and vulcanizing chamber l3 to which they are directed, after leaving the draw-off roller l2, by aguide roller M. In traversing the drying and vulcanizing chamber l3, the filaments F are supported against sagging by a series of rollers I5; and, upon emerging from said chamber 'said filaments are collected as finished threads on a spool or beam it. The rollers l2, l5 and the collecting beam l6 .may be driven, by any suitable drive means, at a surface speed synchronous with that of the forming cylinder 1 to avoid stretching of the filaments; or they may be differentially driven in respect to said forming cylinder to determine a definite attenuation of the filaments. In either case, the square cross sectional configuration determined by the grooves 8 of the cylinder 1 will persits in the finished threads.

when threads of triangular cross section are desired, the forming cylinder is provided with circumferential grooves having the profile shown at 8a, in Fig. III and at 8b in Fig. VI.

Grooves of an arcuate profile, such as shown at in Fig. IV, will, on the other hand, determine threads of semicircular cross section.

Again, grooves profiled after the manner illustrated at 8d in Fig. V, will predetermine threads of semi-hexagonal cross section.

The above modifications are to be regarded as typical of other profile shapes which may be given the grooves of the forming cylinder in accordance with the cross-sectional configuration desired in the finished threads.

For the purpose of producing rayon from cellulose solutions, my improved apparatus may take the form-illustrated in Fig. VII, where, in addition to, or in lieu of a coagulating chamber, there is provided a receptacle I! for a suitable coagulating solution S", said receptacle being supported at a level well above the receptacle 9 containing the cellulose solution S. Dipping into the coagulating solution S" in the receptacle H is a driven feed roller I8 which serves a contacting applicator roll l9 whereby the coagulating solution is applied to the strands of the cellulose occupying the grooves of the forming cylinder 1' above the doctor roll ID. A

' scraper blade 20 insures even distribution of the coagulant upon the feed roller l8 and in turn, the application of a prescribed regulated amount of said solution to the cellulose strands. After being set by the coagulant, the cellulose strands are drawn from the forming cylinder as filaments F for conduction to a chamber, such as shown at l3 in Fig. I, for drying.

From the foregoing it will be evident that I have provided a very simple method and apparatus whereby synthetic threads of any required cross section may be continuously and expeditiously produced.

Having thus described my invention, I claim:

1. The continuous method of producing synthetic threads which comprises running a cylinder partly submerged in a viscous solution or emulsion so that circumferential forming grooves of said cylinder become filled with the fluid;

coagulating the solution or emulsion carried up,

in the forming grooves of the cylinder solely by adhesion with the groove surfaces; and removing the resulting threads from the cylinder grooves. I

2. The continuous method of producing elastic threads which comprises running a cylinder partly submerged in an aqueous dispersion of rubber or latex so that circumferential forming grooves of said cylinder become filled with the fluid; coagulating the fluid carried up in the forming grooves by the cylinder solely by adhesion with the groove surfaces; removing the resulting threads from the cylinder grooves; and thereupon vulcanizing the threads.

3. The method of continuously p oducing synthetic threads which comprises running a cylinder partly submerged in a viscous solution or emulsion so that circumferential forming grooves of said cylinder become filled with the fluid; applying a suitable liquid coagulating agent to the solution carried up in the forming grooves of the cylinder solely by adhesion with the groove surfaces; and removing the resulting threads from the cylinder grooves.

4. The continuous method of producing'synthetic threads which comprises running a cylinder partly submerged in a viscous solution or emulsion so that the circumferential forming grooves of said cylinder become filled with the fluid, carrying the solution or emulsion solely by its adhesion with the groove surfaces, forming the threads to the shape of the grooves of the cylinder, coagulating the solution or emulsion in the cylinder grooves; and removing the resulting threads from the cylinder grooves.

5. The continuous method of producing synthetic threads which comprises running a cylinder partly submerged in a dispersion containing rubber so that the circumferential forming grooves of said cylinder become-filled with the fluid, carrying the dispersion solely by its adhesiorv with the groove surfaces, forming the threads to the shape of the grooves of the cylinder, coagulating the solution or emulsion in the cylinder grooves; removing the resulting threads from the cylinder grooves, and thereupon vulcanizing the threads. I

6. The continuous method of producing syn-.-

thetic threads which comprises running a cylinder partly submerged'in a viscous solution or emulsion so that the circumferential forming grooves of said cylinder become filled with the fluid, carrying the solution or emulsion solely by its adhesion with the groove surfaces, forming the threads to the shape of the grooves of the cylinder, coagulating the solution or emulsion in the cylinder grooves with a liquid coagulating agent; and removing the resulting threads from the cylinder grooves.

. GLEN S. HIERS. 

